Connected Components-based Colour Image Representations of Vibrations for a Two-stage Fault Diagnosis of Roller Bearings Using Convolutional Neural Networks

Roller bearing failure is one of the most common faults in rotating machines.Various techniques for bearing fault diagnosis based on faults feature extraction have been proposed.But feature extraction from fault signals requires expert prior information and human labour.Recently,deep learning algorithms have been applied extensively in the condition monitoring of rotating machines to learn features automatically from the input data.Given its robust performance in image recognition,the convolutional neural network(CNN)architecture has been widely used to learn automatically discriminative features from vibration images and classify health conditions.This paper proposes and evaluates a two-stage method RGBVI-CNN for roller bearings fault diagnosis.The first stage in the proposed method is to generate the RGB vibration images(RGBVIs)from the input vibration signals.To begin this process,first,the 1-D vibration signals were converted to 2-D grayscale vibration Images.Once the conversion was completed,the regions of interest(ROI)were found in the converted 2-D grayscale vibration images.Finally,to produce vibration images with more discriminative characteristics,an algorithm was applied to the 2-D grayscale vibration images to produce connected components-based RGB vibration images(RGBVIs)with sets of colours and texture features.In the second stage,with these RGBVIs a CNN-based architecture was employed to learn automatically features from the RGBVIs and to classify bearing health conditions.Two cases of fault classification of rolling element bearings are used to validate the proposed method.Experimental results of this investigation demonstrate that RGBVI-CNN can generate advantageous health condition features from bearing vibration signals and classify the health conditions under different working loads with high accuracy.Moreover,several classification models trained using RGBVI-CNN offered high performance in the testing results of the overall classification accuracy,precision,recall,and F-score.

Stimulated Raman scattering microscopy on biological cellular machinery

Beneting from the developments of advanced optical microscopy techniques,the mysteries of biological functions at the cellular and subcellular levels have been continuously revealed.Stimulated Raman scattering(SRS)microscopy is a rapidly growing technique that has attracted broad attentions and become a powerful tool for biology and biomedicine,largely thanks to its chemical specicity,high sensitivity and fast image speed.This review paper introduces the principles of SRS,discusses the technical developments and implementations of SRS microscopy,then highlights and summarizes its applications on biological cellular machinery andnally shares our visions of potential breakthroughs in the future.

Wide-Field Vibrational Phase Contrast Imaging Based on Coherent Anti-Stokes Raman Scattering Holography

We propose and implement a wide-field vibrational phase contrast detection to obtain imaging of imaginary components of third-order nonlinear susceptibility in a coherent anti-Stokes Raman scattering （CARS） microscope with full suppression of the non-resonant background. This technique is based on the unique ability of recovering the phase of the generated CARS signal based on holographic recording. By capturing the phase distributions of the generated CARS field from the sample and from the environment under resonant illumination, we demonstrate the retrieval of imaginary components in the CARS microscope and achieve background free coherent Raman imaging.

Photoswitchable vibrational nanoscopy with sub-100-nm optical resolution

Stimulated Raman scattering(SRS)microscopy has shown superior chemical resolution due to the much narrower vibrational spectral bandwidth than its fluorescence counterpart.However,breaking the diffraction-limited spatial resolution of SRS imaging is much more challenging because of the intrinsically weak scattering cross section and inert/stable nature of molecular bond vibrations.We report superresolution SRS(SR-SRS)nanoscopy based on reversible-switchable vibrational photochromic probes integrated with point spread function engineering strategy.By introducing a Gaussian-shaped ultraviolet excitation beam and a donut-shaped visible depletion beam in addition to the pump and Stokes beams,SR-SRS could reach sub-100 nm resolution on photoswitchable nanoparticles(NPs).Furthermore,NP-treated live cell imaging was demonstrated with resolution improvement by a factor of∼4.Our proof-of-principle work provides the potential for SR vibrational imaging to assist research on complex biological systems.

Heliox as a driving gas to atomize inhaled drugs on acute exacerbation of chronic obstructive pulmonary disease： a prospective clinical study

Background Acute exacerbation of chronic obstructive pulmonary disease （AECOPD） is a common condition,which affects not only the quality of life of patients but also their prognosis.The purpose of this study was to explore the effects of an inhaled salbutamol sulfate solution and an inhalation suspension of the glucocorticoid budesonide that were atomized with heliox to treat patients with AECOPD.Methods Twenty-three patients with AECOPD were divided into a treatment group （He/O2=70％/30％） and a control group （N2/O2=70％/30％）.The salbutamol sulfate and budesonide were administered by inhalation twice a day for 7 days.Vital signs,arterial blood gas levels,pulmonary function and the levels of serum myostatin （sMSTN） were measured and lung vibration imaging was performed.Results We found that the PaO2 and PaCO2 values were not significantly different between the two groups at the various time points （P ＞0.05）.There were also no significant differences in any of the parameters of pulmonary function between the two groups.However,after baseline correction,the increase rate of the forced expiratory volume in one second （FEV1）,the forced vital capacity （FVC）,and the maximum minute ventilation （MW） appeared to be significantly increased at some time points compared with the baseline （before treatment） in both groups （P ＜0.05）.Although the values of quantitative lung distribution （QLD） for different regions and the levels of sMSTN were slightly different between the two groups,the repeated measures analysis of variance （ANOVA） revealed that there were no significant differences between the two groups or within any group （P ＞0.05）.Conclusion Although the use of heliox as a driving gas can improve symptoms and benefit patients with AECOPD,the heliox treatment group did not have significant differences in arterial blood gases,lung function,lung vibration response imaging or the levels of sMSTN compared with the control group.（Chinese Clinical Trial Register Center ChiCTR-TRC-00000273）